I came here to suggest a roguelikes episode, and would definitely agree with Epyx Rogue, NetHack and Dungeon Crawl above – while all those games are available on other platforms too, they had a very distinctive look on a DOS text display.
To add another one, you could also talk briefly about One Hundred and One Monochrome Mazes – it’s a pure maze game rather than a roguelike, but it’s a very early PC game, and there aren’t very many games out there that are designed to only work on MDA…
